Control system



May '15,

L. O. REICHELT CONTROL SYSTEM Filed July 8, 1942 2 Sheets-Sheet 1 vENTOR L.O. RE/CHEL T A T TORNEY Patented May l5, i945 QONTROL SYSTEMLester 0. Reichelt, Cranford, N. 3., assigncr to Western ElectricCompany, Incorporated, New York, N. Y., a corporation of New YorkApplication July 8, 1942, Serial No. 450,221

8 Claims.

This invention relates to control systems, and more particularly tocontrol systems for pressure molding presses.

In certain types of molding presses where plastic articles are moldedthrough the application of pressure and heat, the mold members areclosed under a predetermined low pressure, then opened a desireddistance to allow the escapement of gases and subsequently closed underhigh pressure to complete the molding of the article. The time intervalsfor each of these operations are usually of great importance in theaccurate molding of such articles, and to rely upon manual control forthe operation of the press it is possible that the time intervals forthe various actions of the press may not be constant.

An object of the invention is to provide a control system which ishighly efficient in automatically causing operation of an apparatusthrough various cycle portions at constant given time intervals.

With this and other objects in view the invention comprises a controlsystem, particularly for molding presses wherein fluid control means isemployed to actuate the.press, electrical means being adapted to controlvalves of the fluid control means to cause operation of the press undervaried pressures between varied positions in given varied time limits.

Other objects and advantages will be apparent from the followingdetailed description when considered in conjunction with theaccompanying drawings, wherein Fig. l is a schematic front elevationalview of a molding press and the fluid control means therefor, and

Fig. 2 is a wiring diagram illustrating the electrical control systemfor the structure shown in Fig. 1.

Referring now to the drawings, attention is first directed to Fig. 1,which illustrates schematically a molding press, indicated generally atHI, having a fixed mold member ii mounted in any suitable manner such asbetween vertical supports l2 and id. The supports in the presentillustration are mounted upon a cylinder it in which a piston I6 isdisposed. A piston rod ll connects the piston 88 to a mold member i8disposed in general alignment with the mold member I I. The mold membersl i and 93 are provided with suitable cavities i9 and 20, respectively,formed of the contours desired for the molding of an article therein.The mold members may also be provided with suitable means (not shown) toheat them to the desired temperature for the molding operations. The

detailed structure of the mold member and the press in general is notbelieved necessary for a clear understanding of the invention. Attentionis directed to limit switches which may be respectively termed lower andupper limit switches 2i and 22. These limit switches may be mounted sothat their control levers 23 and 24 respectively may be actuated by anarm 25 movable with the mold member Id. In the present illustration thelimit switches are mounted upon the vertical support I2.

A fluid control means is connected to the cylinder IE to cause movementof the piston 16 to close the mold (including the mold members H and i8)under a low pressure, open the mold a given distance, close the moldagain under a high pressure and finally open the mold by returning themold member It to its normal or loading position (Fig. 1). This fluidcontrol means begins with a supply line 28 which is adapted to supply afluid, such as air, under a sufficiently high pressure to a fluid line29. A fluid line 30 connects the fluid line 29 with a lower end 3| ofthe cylinder l5, while a fluid line 32 connects the fluid line 29 withan upper end 33 of the cylinder.

Considering first the fluid line 30, it will be noted that a reducingvalve 35 is disposed therein, this valve being of a conventional typeand adapted to reduce the pressure of the fluid in the line 30 betweenthis valve and the cylinder to a given high pressure. Also, in the fluidline 3d is a solenoid-operated valve 36 of a conventional type adaptedto open the line and allow the fluid therein to pass to the cylinderunder the full pressure controlled by the valve 35. Another valve 37 isdisposed in the line 30, this valve being of a type to control the speedof the fluid to the lower portion 3! of the cylinder. Thus there isprovided in the line 30, the valve 35 to control the pressure of thefluid in the line, the valve 36 to open and close the line 30 and thevalve 3? to control the speed of the fluid in the line to the cylinder.

The line 32 is substantially identical with the line 36 in that there isprovided a reducing valve 66, a solenoid-operated valve ll, and a speedcontrol valve 52, therein. The solenoid-operated valve d! opens the line32 to supply fluid under a pressure controlled by the valve to and at aspeed controlled by the valve t2.

Attention is now directed to another fluid line @2, which extends fromthe line 29 to a. connection 5% in the line 30, and thus through theadjacent part of the line 30 to the lower end 3| of haust lines.

line 28 will pass to the lower portion 3| of the cylinder under apressure controlled by the valve 45 and at a speed controlled by thevalve 41. The lines 30 and 43 with their various valves may be termedhigh pressure and low pressure lines, as it is through these lines thatthe fluid under diiferent pressures causes the piston with the movablemold member to be moved upwardly under high and low pressures.

The fluid lines to supply fluid under varying pressures to the cylinderhave been described. Linked with these lines must of necessity be ex-Attention is therefore directed to line 30 where, at connection 50, isprovided an exhaust line In the exhaust line 51 a solenoid-operatedvalve 52 is disposed to open and close the line; also, a speed controlvalve 53 is disposed to control the speed of movement of the exhaustfluid from the cylinder and to function, through the fluid it controls,as a cushioning means for the piston I6. A similar exhaust line 54 leadsfrom the line 32 at connection 55 and is provided with asolenoid-operated valve 56 and a speed controlled valve 51. This line isopened during the upward movement of the piston to allow the fluid abovethe piston to escape at a given speed controlled by the valve 51. I

Thus far there have been described high and low pressure feeding linesfor moving the mold member I8 upwardly and the feeding line to move themold member downwardly, together with the exhaust lines linkedtherewith. Such lines are, as will hereinafter be described, under acomplete control of the electrical units and their circuits shown inFig.2. However, to condition the apparatus so that, if desired, it maybe under manual control during testing of the apparatus, another fluidline 60 is connected to the line 29 and is opened, through asolenoid-operated valve 6|, to supply fluid to a manually controlledvalve 62. The valve 62 may be of the four-way type connected not only tothe line 60 but to supply lines 63, 64 and an exhaust line 65. The lines63 and 64 communicate with lines 30 and 32 at connections 66 and 61respectively. Through this arrangement the manually operated valve 62when in the position shown, will, through the opening of the valve 6|,permit fluid under pressure to pass through line 60, valve 62, line 63,connection 66, and through the portion of line 30 to the lower portion3| of the cylinder under the control of the valve 31. At the same timean exhaust line is provided for the fluid above the piston to passthrough line 32 to connection 61, line 64, valve 62, and exhaust line 65under the control of the valve 42.- By turning the valve 62 a sufflcientdistance through the aid of its handle 69, the circuits just describedmay be closed and another set of circuits opened to supply fluid to theupper portion 33 of the cylinder and exhaust the fluid from the lowerportion 3| of the cylinder. These circuits may be traced through lines29 and 60, valve 62, line 64, to connection 61, valve 42, line 32, tothe cylinder. The exhaust line for the lower portion of the cylinder maybe traced from the cylinder, through line 30 and valve 31, connection66, line 63, valve 82, and exhaust line 65. All of the valves previouslydescribed are standard and thus commercially known. It is therefore notbelieved necessary to show and specifically describe them for a clearunderstanding of the invention.

Attention is now directed to the electrical control means illustrated inFig. 2 and linked with the fluid control means of Fig. 1. In the presentembodiment lines 1| and 12 from a 440-volt source of electrical energyare provided. One circuit adapted to energize a relay 13 when a switch14 is closed, may be traced from line H at connection 15 through switch14, relay 13, to line 12 at connection 16. Another circuit controlled bythe relay through its contact 11 may be closed thereby to direct theelectrical energy through a primary winding 18 of a transformer 19. Thelast mentioned circuit may be traced from line 1| at connection throughcontact 11 when closed, through winding 18 to line 12 at connection 8|.A secondary winding 82 of the transformer 19 will thus supply a l10-voltelectrical energy to lines 83 and 84. When this electrical energy issupplied to the lines 83 and 84, a visual signal or lamp 85 isilluminated, it being in a circuit traced from line 83 at connection 86to line 84 at connection 81. As soon as the switch 14 is closed toenergize the relay and supply the 440-volt electrical energy to thetransformer, the manual control means for the fluid system illustratedin Fig. 1 is rendered effective for operation. This results from theopening of the valve H in the line 60 (Fig .1). The operation of thevalve 6I is brought about through the energization of a solenoid 90associated therewith, the solenoid being in a circuit which may betraced from line 83 at connection 9| through a normally closed contact92 and solenoid 90 to line 84 at connection 93. Another circuit istapped into the last mentioned circuit at connection 94 and extendsthrough a visual signal or lamp 95 to line 84 at connection 96. Thevisual signal 95 indicates that the control system has been conditionedfor the manual operation of the apparatus.

To render the manual operating means ineffective and cause automaticoperation of the apparatus, a switch 98 is moved from its upper positionshown, to complete a. circuit from line 83 at connection 99, through theswitch 98 in its lower position, a relay I00, to line 84 at connectionIN. The switch 98 need be moved to its lower position only long enoughfor the energization of the relay I00, after which it may be allowed toreturn to its upper postion (shown). However, upon energization of therelay I00, the contact 92 will be opened, opening the circuit to thesolenoid 90 and efiecting closing of the valve 6|. Thus the manualcontrol means is rendered ineffective. Energization of the relay I00also closes contacts I02. I03 and I04. The contact I02 in closing,completes a locking circuit through the relay I00 which may be tracedfrom line 83 at connection I06 through a switch I01, contact I02, relayI00, to line 84 at connection IOI.

Returning momentarily to the switch 98, it will be observed that anothercircuit will be completed with the circuit through the relay I00 uponthe movement of this switch to its lower position, the circuit beingtraced from line 83 at connection 99 through switch 98 in its lowerposition, a visual signal or lamp I08, to line 84 at connection I09. Thevisual signal I08 indicates that the automatic control system is readyfor operation. This signal remains energized, after the movement of theswitch 98 to its upper position, through a circuit controlled by thelocking circuit of the relay or contact I02 and may be traced from line83 at aeraceo connection M6, through the normally closed switch itl,contact I62, through the visual signal or lamp 568, toline 8d atconnection I09.

The contacts I63 and IM serve to close normally open portions in thelines 83 and 8s respectively; thus the closing of the contacts I03 andIilt thorugh the energization of the relay I06 closes the lines 83 andB4 to supply electrical energy for the remaining units in the controlsystem. The function of the control system thus far described conditionsthe automatic features thereof for operation. All that remains for theoperator to do at this point is to close a switch I I0.

By closing the switch I ID a circuit is completed from line 63 atconnection 99 through switch 98 in the upper position shown, switchIll), a normally closed stop switch III, a relay II2, to line 3 3 atconnection lid. The relay H2 is thus energized, closing contacts H5, H6,Ill and H8 and opening contact H9. The closing of the contact M6 willcondition a locking circuit for the relay ll 2 which may be traced fromline 83 at connection 320 through closed contact I I5, a contact I2Iwhen closed, a relay IIZ, to line 8d at connection lid. The closing ofthe contact H6 completes a circuit through a time control relay I23which may be traced from line 83 at connection I26 through closedcontact I I6, relay I23, to line M at connection I25. The closing of thecontact II! will complete a circuit through another time control relayiZ'I, which circuit may be traced from line 63 at connection I26 throughclosed contact Ml, relay I27, to line 86 at connection I29. Energizationof the relay I211 will close the contact l2I to complete the lockingcircuit through the relay M2 by closing its contact H'i. Closure of thecontact H8 completes a circuit for a relay I30 which may be traced fromline 63, at connection 53E through relay I30, closed contact I I6, toline hit at connection 532. The contact I I9 opens a circuit to'a relay533, the purpose of which will hereinafter be described.

Attention is now directed to the relay I30, which is energized throughthe closing of the contact M6 to close contacts I35, I36 and I31 andopen a contact M56. The closing of the contact (136 will complete acircuit through another time control relay I 36, which circuit may betraced from line 93 at connection MI through contact ltd, normallyclosed contact M2, relay I46, to line,

as at connection Itil. Upon energization of the relay I lt through thecompletion of its circuit, a

locking circuit is completed through the closingof a contact hit, thiscircuit being traced from line 68 at connection M36 through contact I35,relay M6, to line 6 3 at connection M3. There are two other contactsunder the control of the relay M6, the relay when energized closing acontact M7 and opening a normally closed contact I56. The closing of thecontact m completes a circuit through an indicating signal or lamp M9,the circult being traced from line 83 at connection I56, through contactMi, lamp I69, to line 34 at con nection ifil. The contact MB is in thecircuit for the relay I83 and also functions to control this relay.

Referring now to the relay I27, this relay provides its own lockingcircuit through the closing of its contact 963, this circuit beingtraced from line 85 at connection IEQ, through contact I56, the

relay iii, to line 6% at connection I29. Consider now the contacts forthe relay I23 indicated at M6, E66 and I617. Upon energization of therelay E23, contacts 55 and I66 will be closed and the contact it'll willbe opened. The contact E will complete a locking circuit for the relayI23, which circuit may be traced from line 83 at connection I50, throughcontact I55, relay I23, to line 84 at connection I25. The contact I56 isa part of the circuit for the relay I33 and functions with the contactsH6 and M8 to condition this circuit, which, when closed through theclosing of these contacts, may be traced from line 83 at connection I60,through contacts H9 and I56, relay I33, and contact 58, to line 8 5 atconnection I6 I. The contact I51 opens a circuit to a relay I62, thiscircuit being traced from line 83 at connection I63, through contact I51when closed, relay I62,

to line 84 at connection I66.

Attention is now directed to contacts I36, itl and I38 of the relay I30.The contact I68 is opened upon energization of its relay, renderingineffective circuits adapted to actuate what might be termed the downvalve M and the bottom exhaust valve 52. The contacts I36 and I31,however, are closed and complete circuits through solenoids I66 and I6'Irespectively, to cause opening of their respective valves 66 and 56which might be termed the low pressure valve and the top exhaust valve.The circuit through the solenoid I66 may be traced from line 83 atconnection I68 through contact I36 when closed, solenoid I66, to line 8%3 at connection I69. The circuit for the solenoid I61 may be traced fromline 83 at connection Ht, through contact I31, solenoid IN, to line 8dat connection Ill. Thus it will be apparent that upon actuation of theswitch H0 and after the preceding circuits have functioned to conditionthe automatic portion of the system for functioning, the valves 36 and56 will be opened to cause upward movement of the piston under low pressure, resulting from the opening of the valve 56 and the exhausting ofthe fluid above the piston through the opening of the valve 56.

At this time attention is directed to the time control relays I23, I21and I 60. They have their important functions in the operation of thecontrol system. It should be understood that these relays areschematically shown, the letters T present thereon are to indicate thatthey are time control relays of a conventional type, energizable uponthe completion of their circuits and adapted to hold their contacts inthe attracted positions for given lengths of time.

Considering now the operation of. the control system, let it be assumedthat the press is in its open position shown in Fig. 1. Upon closing theswitch 16 (Fig. 2), the circuit is completed through the relay I3,closing its contact I? to complete the circuit to supply electricalenergy to the transformer "I9. As a result, the desired electricalenergy is supplied to the lines 63 and 86. The visual signal 65 isilluminated, indicating to the operator that the electrical energy issupplied tothe lines 86 and 85. With the control system thus arranged,the operator may at this time, if he so desires, cause operation of thepress through the actuation of the valve 62, as the line 60 has beenopened through the opening of the valve 6|, this occurring by theenergize.- tion of the solenoid 90. At the same time the lamp or visualsignal will be illuminated to indicate that such has taken place. Thecontrol system remains in this condition as lon as de sired. By movingthe valve 62 into a position so that the fluid under pressure will bedirected through the line 63, the speed of this fluid will be controlledby the valve 31 before it enters the lower portion 3| of the cylinderIS. The valve 62 is so constructed that upon providing communicationbetween the line 60 and the line 63, communication will besimultaneously established between the lines 64 and 65 so as to allowthe fluid above the piston in the cylinder to exhaust through lines 32and 64, the valve 62, and the exhaust line 65. In this manner the moldmember I8 may be moved relative to the mold member II into closedposition. if so desired. To move the mold member I8 away from the moldII, the valve 62 may be moved into another position to connect the line64 with the line 60 and the line 63 with the exhaust line 65, and inthis manner the piston will be moved downwardly, the fluid beneath thepiston exhausting through lines 30 and 63, the valve 62, and the exhaustline 65. In such instance the speed control valves 31 and 42 serve tocontrol the speed of the fluid passing through their lines.

Consider now the automatic control feature of the system. First, let itbe assumed that the press is in the open position, and that thepreviously described circuits have been completed through the closing ofthe switch 14. IA; this time the switch 98 may be moved to its lowerposition to momentarily close the circuit through the relay I00, atwhich time the locking circuit for the relay, through its contact I02and the normally closed switch I01, is completed, after which the switch98 may be allowed to return to its normal or upper position. Uponenergization of the relay I00, the attraction of its contacts willrender the manual control portion of the system inoperative through theopening of the contact 92 and will close the adjacent brakes in thelines 83 and 84 at the contacts I03 and I04. At this time the visualsignal 85 ceases to be illuminated and a new signal I08 is illuminatedto indicate that the automatic feature of the system is ready foractuation. An additional step, however, is necessary to start theautomatic feature of the control system, this being the closing of theswitch IIO. At this time the relay H2 is energized, attracting itscontacts and thus causing energization of the relay I30 in addition tothe time relays I23, I21 and. I40.

The moment the switch I I is closed circuits are completed through thecontacts I36 and I31 of the relay I30 to cause energization of thesolenoids I68 and I61 therein, to open their respective valves 46 and56. Attention is now directed to Fig. 1, where, with the valves 46 and56 open, the fluid control portion of the system is caused to allowfluid under low pressure governed by the reducing valve 45 to pass at aspeed controlled by the valve 41 into the lower portion of the cylinderI5 to thus move the mold member I8 into closed position relative to themold member II under the said low pressure. The fluid above the pistonescapes through the valve 56 at a. speed controlled by the valve 51.This operation is under the control of the time relay I21, which in thepresent embodiment is set for deenergization after flve seconds haveelapsed. At the completion of this time interval and upon deenergizationof the relay I21, the contact I2I will be opened, opening the lockingcircuit for the relay H2, thus effecting deenergization of this relay.As a result, contacts H5, H6, H1 and 8 will be opened, and contact II!)will be closed, these contacts being under the control of the rela II2.At the same time, through the opening of the contact 8 the relay I30will be deenergized, effecting opening of the contacts I35, I36 and I31and the closing of the contact I38. Thus after the completion of thegiven time interval, which in the present instance is five seconds, thevalves 46 and 56 will be allowed to close through the deenergization ofthe solenoids I66 and I81.

The closing of the contact I38 will complete two circuits, one of whichmay be traced from line 83 at connection I15 through the lower limitswitch 2|, contact I38, a normally closed contact I11 of the relay I33,through the upper limit switch 22, connections I18 and I13, solenoidI80, to line 84 at connection I8I. The other circuit may be traced fromline 83 at connection I18 through the lower limit switch 2|, contactsI38 and I 11, the upper limit switch 22, a solenoid I82, to line 84 atconnection I83. When these circuits are closed and their respectivesolenoids I80 and I82 energized, the associated valves 4| and 52 will beopened to cause downward movement of the mold member I8 away from themold member I I. The limit of this movement is under the control of theupper limit switch 22, the arm on the mold member I8 causing opening ofthis limit switch when the mold member reaches a given distance belowthe upper mold member. When the upper limit switch 22 is opened thecircuits controlling the valves 4| and 52 through their solenoids I80and I82 will be allowed to close and the press will remain at rest. withthe mold member in its lowered position for a given length of timecontrolled by the time relay I40. The purpose of opening the moldmembers, for example when molding plastic materials in heated molds, isto allow any gasses, resulting from the first step of the moldingoperation, to escape prior to the final molding step.

During the energization of the time control relay I40, it will beobserved that the contact I48 thereof is open, holding the circuit tothe relay I33 open until the expiration of the time interval in whichrelay I is energized, which in the present instance is eight seconds.Thus, upon rapid closing of the press and allowing five seconds for thisoperation and for the press to remain closed during the first step ofthe molding operation, there is an additional three seconds allowedthrough the control of the relay I40 for the opening of the press andthe maintaining of the press in the open position. At the expiration ofeight seconds the relay I40 becomes deenergized, allowing contacts I andI41 to open and the contact I48 to close.

At this time the signal I49 will be deenergized and the circuit to therelay I33 will be closed due to the fact that the contact II9 haspreviously been closed through the deenergization of the relay I I2 andthe contact I 56 is being held closed by the relay I23. Thus theenergization of the relay I33 will open the contact I11 and closecontacts I and I86. The last mentioned contacts 85 and I86 completecircuits to cause upward movement of the mold member I8 under highpressure. The contact I85 completes the circuit to control the topexhaust valve 56 for the escapement of the fluid above the piston, whilethe closure of the contact I86 completes a circuit through a solenoidI88 for opening the valve 36. The last mentioned circuit may be tracedfrom line 83 at connection I89 through contact I86, solenoid I88, theline 84 at connection I80. The energization of the solenoid I88 willopen the line 30 to allow fluid at a high pressure controlled by thevalve 35 to pass into the lower portion 3| of the cylinder at a speedcontrolled by the valve 31 to move the mold member I8 again into closedposition, this time under high pressure to complete the molding of thearticle.

The mold remains closed a definite time interval under the control ofthe relay I23, which has .and returned-to its normal position.Furtherbeen energized since the closing of the switch H8 and during theprevious operations of the press. In the present embodiment the timeinterval of energization of this relay is three minutes, leavingapproximately two minutes and fifty-two seconds for the mold to remainclosed under high pressure, the other eight seconds having beenpreviously taken by the other operations, namely the original closing ofthe press under low pressure, the opening of the press under the controlof the time relay I48, and the second closing of the press under highpressure. At the expiration of the three minutes the time relay I23 willbe deenergized, effecting opening of the contacts I55 and I56 and theclosing of the contact I51. The opening of the contact I55 opens thelocking circuit for the relay I23. The opening of the contact I56 opensthe circuit for the relay I33, the deenergization of which causesopening of the contacts I85 and I86 and the closing of the contact I11.In this manner, at the expiration of the time limit for the energizationof the relay I23, the circuits to the solenoids I61 and I88 are open,allowing their respective valves 56 and 36 to close.

The closing of the contact I51 will complete the circuit through therelay I62, energizing the relay to close its contact I9I. Thus uponclosure of the contact I11 a circuit for the solenoid I88 is completedfrom line 83 at connection I15 through the limit switch 2 I, contactsI38, I11 and mi, through solenoid I88, to line 84 at connection I8I. Atthe same time a circuit is completed through the solenoid I82 and may betraced from line 83 at connection i15 through the limit switch 2i,contacts I38, I11 and I9I, through connections I19 and I18, solenoidI82, to line 88 at connection I83. The portion of the circuit betweenconnections I19 and I 18 extends around the upper limit switch 22 sothat the actuation of this limit switch during the downward movement ofthe mold member I8, will not effect the circuits just described. Thesecircuits cause energization of the solenoids I88 and I82 to open thevalves 4i and 52 respectively, to cause downward movement of the pistonand its mold member I8 until they reach their open positions shown inFig. l, at which time the limit switch 2| will be actuated into openposition to open both circuits to the solenoids I88 and I82, effectingopening of their respective valves. The press is thus in readiness foranother operating cycle, which may be carried out in the same manner.Attention is momentarily directed to the switches I81 and III, the

purpose of these switches being to stop the press, I

by rendering inefiective the control means, when desired.

At the completion of each operating cycle the control system returns tothe point where the operation of the switch 88 is required to start anew operating cycle. It will, therefore, be ap parent that in thecontrol system there are various parts linked together to perform thevarious functions desired. One part includes the fluid control meanshaving a manual control feature and an automatic control feature. Linkedwith these are the electrical features to render the manual controloperable or inoperative and to carry out automatically a complete cycleof events to move the mold member from a normal open position into aclosed position under a given pressure. to open the press a limiteddistance for a given length of time and subsequently close the pressunder a different pressure for another given length of time, after whichthe press is opened more, the visual signals are provided to indicatethe condition of the control system, whether: it be in readiness formanual operation or automatic control, and to further indicate variousstages of the automatic control during the operation of the press.

Although specific improvements of the invention have been shown anddescribed, it will be understood that they are but illustrative and thatvarious modifications may be made therein without departing from thescope and spirit of this invention as defined by the appended claims.

What is claimed is:

l. A control system for an apparatus having a I unit with membersadapted for relative movement into closed. and open positions throughmovement of a piston in a cylinder by fluids under pressure to closingand opening ends of the cylinder, the control system comprising anopening fluid line for directing a fluid under pressure to the openingend of the cylinder, low and high pressure closing fluid lines fordirecting fluids under varied pressures to the closing end of thecylinder, valves in the fluid lines, operable solenoids for actuatingtheir respective valves, and electrical means to automatically operatethe solenoids at given time intervals to actuate first the valve in thelow pressure closing fluid line to close the members, then actuate thevalve in the opening fluid line to open the members, then actuate thevalve in the high pressure fluid line to again close the members, andagain actuating the valve in the opening fluid line to open the members.

2. A control system for an apparatus having a unit with members adaptedfor relative movement into closed and open positions through movement ofa piston in a cylinder by fluids under pressure to closing and openingends of the cylinder, the control system comprising an opening fluidline for directing a fluid under pressure to the opening end of thecylinder, low and high pressure closing fluid lines for directing fluidsunder varied pressures to the closing end of the cylinder, valves in thefluid lines, operable solenoids for actuating their respective valves,and electrical means to automatically operate the solenoids at giventime intervals to actuate first the valve in the low pressure closingfluid line to close the members under a given pressure, then actuate thevalve in the opening fluid line to open the members, then actuate thevalve in the high pressure fluid line to again close the members under ahigher pressure, and again actuating the valve in the opening fluid lineto open the members.

3. A control system for an apparatushaving a unit with members adaptedfor relative movement into closed and open positions through movement ofa piston in a cylinder by fluids under pressure to closing and openingends of the cylinder, the control system comprising a supply line for afluid under pressure, an opening fluid line extending from the supplyline to the opening end of the cylinder, low and high pressure closingfluid lines extending from the supply to the closing end of thecylinder, reducing valves disposed in the closing fluid lines to varythe fluid pressures therein, valves in the opening and closing fluidlines, operable solenoids for actuating their respective valves, andelectrical means to automatically operate the solenoids at given timeintervals to actuate first the valve in the low pressure closing fluidline to close they members, then actuate the valve in the opening fluidline to open the members, then actuate the valve in the high pressurefluid line to again close the members, and again actuating the valve inthe opening fluid line to open the members.

4. A control system for an apparatus having a unit with members adaptedfor relative movement into closed and open positions through movement ofa piston in a cylinder by fluids under pressure to closing and openingends of the cylinder, the control system comprising a supply line for afluid under pressure, an opening fluid line extending from the supplyline to the opening end of the cylinder, low and high pressure closingfluid lines extending from the supply to the closing end of thecylinder, reducingvalves disposed in the closing fluid lines to vary thefluid pressures therein, means disposed in the opening and closing fluidlines to control the speed of the fluid therethrough, valves in theopening and closing fluid lines, operable solenoids for actuating theirrespective valves, and electrical means to automatically operate thesolenoids at given time intervals to actuate flrst the valve in the lowpressure closing fluid line to close the members, then actuate the valvein the opening fluid line to open the members, then actuate the valve inthe high pressure fluid line to again close the members, and againactuating the valve in the opening fluid line to open the members.

5. A control system for an apparatus having a unit with members adaptedfor relative movement into closed and open positions through movement01' a piston by fluids under pressure directed to the opening andclosing ends of the piston, the control system comprising an openingfluid line for directing a fluid under pressure to the opening end ofthe piston, a high pressure fluid line for directing fluid under a givenhigh pressure to the closing end of the piston, a low pressure fluidline for directing fluid under a given low pressure to the closing endof the piston, normally closed valves in the fluid lines, operablesolenoids adapted to open the valves, means to cause operation of thesolenoid for the valve in the low pressure line to cause closing of themembers, and a timing element adapted to operable solenoids adapted toopen the valves, means to cause operation oi. the solenoid for the valvein the low pressure line to cause closing of the members, a timingelement adapted to render the last named means ineffective after a givenlength of time and to cause energization of the solenoid for the valvein the opening fluid line to cause opening of the members, and meansunder the control of one of the members to cause deenergization of thelast mentioned solenoid.

7. A control system for an apparatus having a unit with members adaptedfor relative movement into closed and open positions through movement ofa piston by fluids under pressure directed to the opening and closingends of the piston, the control system comprising an opening fluid linefor directing a fluid under pressure to the opening end or the piston, ahigh pressure fluid line for directing fluid under a given high pressureto the closing end of the piston, a low pressure fluid line fordirecting fluid under a given low pressure to the closing end of thepiston, normally closed valves in the fluid lines, operable solenoidsadapted to open the valves, means to cause operation of the solenoid forthe valve in the low pressure line to cause closing of the members, atiming element adapted to render the last named means ineflective aftera given render the last named means ineffective after a given length oftime and to cause energization of the solenoid for the valve in theopening fluid line to cause opening of the members.

6. A control system for an apparatus having a unit with members adaptedfor relative movement into closed and open positions through movement of.a piston by fluids under pressure directed to the opening and closingends of the piston, the control system comprising an opening fluid linefor directing a fluid under pressure to the opening end of the piston, ahigh pressure fluid line for directing fluid under a given high pressureto the closing end of the piston, a low pressure fluid line fordirecting fluid under a given low pressure to the closing end of thepiston, normally closed valves inv the fluid lines,

length of time and to cause energization of the solenoid tor the valvein the opening fluid line to cause opening of the members, means tocause deenergization of the last mentioned solenoid,

and time controlled means to cause operation 01' the solenoid for thevalve in the high pressure fluid line.

8. A control system for an apparatus having a unit with members adaptedfor relative movement into closed and open positions through movement ofa piston by fluids under pressure directed to the opening and closingends of the piston, the control system comprising an opening fluid linefor directing a fluid under pressure to the opening end of the piston, ahigh pressure fluid line for directing fluid under a given high pressureto the closing end of the piston, a low pressure fluid line fordirecting fluid under a given low pressure to the closing end of thepiston, normally closed valves in the fluid lines, operable solenoidsadapted to open the valves, means to cause operation of the solenoid forthe valve in the low pressure line to cause closing of the members, atiming element adapted to render the last named means ineifective aftera given length of time and to cause energization of the solenoid for thevalve in the opening fluid line to cause opening of the members, meansto cause deenergization of the last mentioned solenoid, time controlledmeans to cause operation of the solenoid for the valve in the highpressure fluid line, and means operable after a given length of time torender inoperative the last mentioned solenoid and again cause operationor the solenoid for the valve in the opening fluid line.

LESTER O. REICHELT.

